1. Field of the Invention
The present invention relates generally to differentials for use in automotive drivelines and, more particularly, to a one piece differential bearing adjuster lock.
2. Discussion of the Related Art
Many of the differential assemblies used in automotive drive axles include a planetary gear set which is supported within a differential housing to facilitate relative rotation between a pair of output shafts. For example, in parallel-axis differentials, the gear set typically includes a pair of helical side gears that are splined to the ends of axle shafts and which are meshed with paired sets of helical pinions journalled in gear pockets formed in the differential housing. Since the gear pockets are parallel to the rotary axis of the differential housing, the pinions rotate on axes and are parallel to the common axis of the output shafts and the side gears. In response to speed differentiation between the output shafts, the torque transmitted through meshed engagement of the side gears and pinions generates thrust forces that are exerted by the gear components against the wall surface of the gear pockets and other thrust surfaces within the differential housing to frictionally limit such speed differentiation and proportion torque between the output shafts.
In addition, most automotive drive axles include a hypoid gear set for changing the direction of power transmission from an axis parallel to the direction of vehicle travel to an axis perpendicular thereto. The hypoid gear set includes a ring gear coupled to the differential housing and a pinion gear journally supported within the axle housing. To facilitate proper function of the drive axle assembly, the differential is mounted on a pair of slidable differential bearings. Typically, the differential bearings are positioned using an externally threaded hollow tube commonly referred to as a differential bearing adjustment nut.
The differential bearing adjustment nut is useful for setting both differential bearing preload and hypoid gear lash. The adjustment nut also provides a load surface for the differential bearing under normal operation. As such, this load surface realizes both axial and torsional loads imparted by the rotation of the differential housing. The axial loads are absorbed by the threaded interface of the adjustment nut with the machined axle housing. The torsional loads are resisted by a locking system that prevents the adjustment nut from rotating. Commonly, a two-piece locking system is utilized to couple the adjustment nut to the axle housing via a bearing cap.
Unfortunately, existing locking systems require an assembler to handle a wire form and a threaded fastener to perform this function. In addition, the assembler must subsequently start the thread in a tapped hole previously machined in the bearing cap and subsequently seat the threaded fastener within a given torque range. During assembly, this process often includes the steps of retrieving a pneumatic torque gun, aligning a socket with the bolt head and actuating the torque gun until the desired torque level has been reached. While the aforementioned process has been useful in retaining the adjustment nut from rotating during operation, it is costly due to the need to handle and install two separate components. Furthermore, the use, calibration, and maintenance of a torque gun is unavoidable. Consequently, there remains a need in the art for a one piece differential bearing adjuster lock and fastener capable of retaining differential bearing adjustment nuts without the use of torque applying tools.
The present invention provides a drive axle assembly for a motor vehicle including an axle housing, a differential bearing, a differential assembly, an adjustment nut and an adjuster lock. The differential assembly is rotatably supported within the axle housing by the differential bearing. The differential bearing is coupled to the axle housing via a bearing cap having an aperture formed therein. The adjustment nut has at least one retention aperture and is engaged with the differential bearing such that rotation of the adjustment nut axially displaces the differential bearing. The adjuster lock includes a first portion and a second portion. The first portion has a barb disposed in the bearing cap aperture. The second portion has a first lock pin disposed in the retention aperture thereby restricting the adjustment nut from rotating relative to the bearing cap.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.